DIY ceramic exhaust coating update

[grahambell]

Following up from the earlier thread, finally got round to fitting the new manifold treated with the brushed on ceramic coating from www.racestuff.co.uk

So does it reduce exhaust temperatures?

Well, after arriving at Custom Chrome who were making up a custom system from the manifold back I tried taking a temp reading off one of the original downpipes with the engine idling. Problem was it fluctuated so much (by tens of degrees) all I could tell for certain that it was something over 100 C

Best guess from the way it went was around 140 C

Got back home with the new system on, took reading off downpipe on new coated manifold in near to same spot as I could and got much steadier reading - of around 250 C!

However, as the engine sat there idling this fell rapidly to around 140 C on one downpipe and around 100 C on the other.

Guess I really needed to have had engine left at idle for exact same amount of time after a run to have got truly comparable results, and the car certainly had a bit longer to cool prior to the 'before' test.

Even so, the 'before' reading was done with a standard system with cast iron manifold and steel downpipes whereas the 'after' was with a tubular four branch so it wouldn't have been directly comparable anyway.

I can say though that on the way back the temp needle was slightly lower than normal, but can't say if that was down to coating, the different exhaust or any other factor.

So can't tell you anything conclusive I'm afraid guys. Still, even if all the stuff does is keep the manifold satin black rather than rusty brown (or black with white bits like VHT goes) then it'll still have been worth doing.

[stevieturbo]

How were you measuring temperatures ??

No matter how good those IR things say they are, surface material, and colour will skew the readings.
Not sure by how much though. There was an article on Autospeed about it a year or 2 ago.

[grahambell]

Hi Steve,

Yes, used one of those laser/IR guns.

[sesat]

Hi Graham. Those IR thermometers work quite well when surface relfectivity is kept constant. Does a friend have a thermocouple handy? You'll just need to have it held to the pipe with constant force/pressure.

[Marquis_Rex]

Porsches from the 4 valve 928 to the later air cooled 911s use ceramic coated exhaust ports as standard. On the air cooled motors it is done, in conjuntion with a very short exhaust port, to minimise thermal loading of the cooling system- i.e air flow around the fins.
It has the added benefit on the water cooled cars in reducing catalyst light off times, by reducing thermal loss at the exhaust manifolding/ports- ie the heat rejected to coolant to conserve the thermal energy for the close coupled catalyst for an advantage during Euro 2 or more emissions compliance.

[chuntington101]

Marquis_Rex said:

Porsches from the 4 valve 928 to the later air cooled 911s use ceramic coated exhaust ports as standard. On the air cooled motors it is done, in conjuntion with a very short exhaust port, to minimise thermal loading of the cooling system- i.e air flow around the fins.
It has the added benefit on the water cooled cars in reducing catalyst light off times, by reducing thermal loss at the exhaust manifolding/ports- ie the heat rejected to coolant to conserve the thermal energy for the close coupled catalyst for an advantage during Euro 2 or more emissions compliance.

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

and cermaic caotings are good for turbo applications as they keep all the heat in the gasses, thus helping spool/lag.

thanks CHris.

[rev-erend]

chuntington101 said:

Marquis_Rex said:

Porsches from the 4 valve 928 to the later air cooled 911s use ceramic coated exhaust ports as standard. On the air cooled motors it is done, in conjuntion with a very short exhaust port, to minimise thermal loading of the cooling system- i.e air flow around the fins.
It has the added benefit on the water cooled cars in reducing catalyst light off times, by reducing thermal loss at the exhaust manifolding/ports- ie the heat rejected to coolant to conserve the thermal energy for the close coupled catalyst for an advantage during Euro 2 or more emissions compliance.

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

and cermaic caotings are good for turbo applications as they keep all the heat in the gasses, thus helping spool/lag.

thanks CHris.

Re pistons :

Excellent until you get a chip.. them you have a hot spot...

OK on race engines that have a short lift but of less benefit on a production car.

Benefit is in thge range 1 ~ 1.5 % better heat to power.

[HarryW]

rev-erend said:

Re pistons :

Excellent until you get a chip.. them you have a hot spot...

OK on race engines that have a short lift but of less benefit on a production car.

Benefit is in thge range 1 ~ 1.5 % better heat to power.

Rev are you saying you get 1-1.5% more power or 1-1.5% less heat or is both . Only asked as the last set of pistons Paul fitted to my rebuild are 'painted/cam coated' don't relish the thought of them chipping but like the idea of a free extra 1% power .

[Pigeon]

chuntington101 said:

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber.

In the days of leaded petrol you used to get ceramic-coated combustion chambers for free I suspect I've got them and it needs to come off...

[chuntington101]

Pigeon said:

chuntington101 said:

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber.

In the days of leaded petrol you used to get ceramic-coated combustion chambers for free I suspect I've got them and it needs to come off...

haha good one Pigeon. i suspect you paid alot less for yours than what it would cost to get an engine fully coated!

Chris.

[chuntington101]

rev-erend said:

chuntington101 said:

Marquis_Rex said:

Porsches from the 4 valve 928 to the later air cooled 911s use ceramic coated exhaust ports as standard. On the air cooled motors it is done, in conjuntion with a very short exhaust port, to minimise thermal loading of the cooling system- i.e air flow around the fins.
It has the added benefit on the water cooled cars in reducing catalyst light off times, by reducing thermal loss at the exhaust manifolding/ports- ie the heat rejected to coolant to conserve the thermal energy for the close coupled catalyst for an advantage during Euro 2 or more emissions compliance.

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

and cermaic caotings are good for turbo applications as they keep all the heat in the gasses, thus helping spool/lag.

thanks CHris.

Re pistons :

Excellent until you get a chip.. them you have a hot spot...

OK on race engines that have a short lift but of less benefit on a production car.

Benefit is in thge range 1 ~ 1.5 % better heat to power.

rev your right, but other forms of coatings have been used in production engines for some time, mainly friction reducing coatings (read an artical on them, they are great! you can coat everthing! lol).

also i dont think the piston coatings are that bad. some performance parts now come coated in the states.

thanks Chris.

[Marquis_Rex]

chuntington101 said:

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

I'm not contradicting you, merely questioning- for if what you say is true on a gasoline engine- a less thermally conductive surface for the combustion chamber- than cast iron cylinder heads and blocks would be an advantage over aluminium in terms of knock resistance. This is not the case as lots of aluminium versions of cast iron engines have shown. When heat loss is more- engines - such as savagely over square versions, NEED more ignition but are quite often not as good at utilising the breathing in terms of combustion efficiency.

If what you said were true- it would suggest that the one of major mechnisms of heat transfer to the burning charge in the combustion chamber is via reflection- which is now minimised with the thermal barrier. is this possible? I don't know.

I think it's at least conceivable that the combustion efficiency due to less heat loss- or the air utlisation is improved, but short of formal back to back testing we'll never know!

[rev-erend]

HarryW said:

rev-erend said:

Re pistons :

Excellent until you get a chip.. them you have a hot spot...

OK on race engines that have a short lift but of less benefit on a production car.

Benefit is in thge range 1 ~ 1.5 % better heat to power.

Rev are you saying you get 1-1.5% more power or 1-1.5% less heat or is both . Only asked as the last set of pistons Paul fitted to my rebuild are 'painted/cam coated' don't relish the thought of them chipping but like the idea of a free extra 1% power .

I remembered it from an old Dave Vizard tuning book on Pinto engines.. there was a small advantage in the coating in the the heat of the burning fuel was better used to expand the gas and push pistons down rather than heating the piston.

Down side was that it's great on a race engine as that is torn apart of a regular basis but a road engine expected to last 100K plus would be a different propersition.

Alloy oxidedises, crematic coatings are brittle, fuel is abrasive and will eventually chip and cause a localised hot spot .. so if you are running a high cr to would be fine one week and have det the next.

But - the world moves on and maybe things have improved but if you are using it - then I would check with some kind of endoscope on a regular basis...

[rev-erend]

chuntington101 said:

rev-erend said:

chuntington101 said:

Marquis_Rex said:

Porsches from the 4 valve 928 to the later air cooled 911s use ceramic coated exhaust ports as standard. On the air cooled motors it is done, in conjuntion with a very short exhaust port, to minimise thermal loading of the cooling system- i.e air flow around the fins.
It has the added benefit on the water cooled cars in reducing catalyst light off times, by reducing thermal loss at the exhaust manifolding/ports- ie the heat rejected to coolant to conserve the thermal energy for the close coupled catalyst for an advantage during Euro 2 or more emissions compliance.

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

and cermaic caotings are good for turbo applications as they keep all the heat in the gasses, thus helping spool/lag.

thanks CHris.

Re pistons :

Excellent until you get a chip.. them you have a hot spot...

OK on race engines that have a short lift but of less benefit on a production car.

Benefit is in thge range 1 ~ 1.5 % better heat to power.

rev your right, but other forms of coatings have been used in production engines for some time, mainly friction reducing coatings (read an artical on them, they are great! you can coat everthing! lol).

also i dont think the piston coatings are that bad. some performance parts now come coated in the states.

thanks Chris.

You are probably right - the world moves on..

[chuntington101]

Marquis_Rex said:

chuntington101 said:

i have heard of lots of benifits of cermaic coating the WHOLE of the cumbustion chamber. alot of the pros come form the things you listed, helps keep the heat in the exhaust!

also cermaic coated pistons "usually" resit det. better than none coated.

I'm not contradicting you, merely questioning- for if what you say is true on a gasoline engine- a less thermally conductive surface for the combustion chamber- than cast iron cylinder heads and blocks would be an advantage over aluminium in terms of knock resistance. This is not the case as lots of aluminium versions of cast iron engines have shown. When heat loss is more- engines - such as savagely over square versions, NEED more ignition but are quite often not as good at utilising the breathing in terms of combustion efficiency.

If what you said were true- it would suggest that the one of major mechnisms of heat transfer to the burning charge in the combustion chamber is via reflection- which is now minimised with the thermal barrier. is this possible? I don't know.

I think it's at least conceivable that the combustion efficiency due to less heat loss- or the air utlisation is improved, but short of formal back to back testing we'll never know!

hmmmmm good points.

and i have no idea on why it made more power. the guy that made the statement was a race engine builder.

your right i guess you can only speculate on power gains unless you carry out back to back testing.

and i thought physics was a sciencs not an art! lol

Chris.

[Marquis_Rex]

chuntington101 said:

and i thought physics was a sciencs not an art! lol

Chris.

If you've seen what I've seen on the supposed fuel economy benefits of valvetronic compared to a standard engine- you'll start to wonder what is science and what is art *LOL*

[350matt]

I tried this when I was working at Cosworth, we coated just the piston crown with a white ceramic susbstance and I have to say it was a disaster, two reasons, firstly the volumetric efficiency dropped off by about 8-10% mainly due to the piston getting hot and staying hot so 'cooking' the inlet charge.

Secondly the coating being very brittle broke away in little pieces which then destroyed the bore , valve seats etc etc

Now things may have moved on in the last few years (this was about 6 years ago) but we did use a reputable company for the coating at the time.

Matt

[mave]

sesat said:

Hi Graham. Those IR thermometers work quite well when surface relfectivity is kept constant. Does a friend have a thermocouple handy? You'll just need to have it held to the pipe with constant force/pressure.

...or you can get stickers with calibrated emissivity. Stick one on the manifold, and use that as your temperature reference. Then adjust the emissivity calibration of the IR camera until you get the same temperature on the manifold as you did on the sticker.

[GreenV8S]

Well the Black Satin has turned up, blimey you don't get much for sixty five quid do you!

Now I just need to find somebody in MK to sand blast the manifolds for me. Any recommendation?

[grahambell]

GreenV8S said:

Well the Black Satin has turned up, blimey you don't get much for sixty five quid do you!

Now I just need to find somebody in MK to sand blast the manifolds for me. Any recommendation?

Yes, the tins are rather small. Did wonder if there'd actually be enough to do the manifold for my Quantum, which has more pipework than any 4 branch I've ever dealt with. In the event I still had about 1/2 tin left so reckon one small tin would do two V8 manifolds no problem.

As for sandblasting in MK, can only suggest Yellow Pages.